Short selling is a way of operation in the stock and futures markets. This is the opposite of doing more. Theoretically, it is to sell the goods first and then buy them back. Generally, the regular short-selling market has a neutral warehouse to provide a platform for borrowing goods. This model can profit in the wave band of falling prices, that is, borrowing goods at a high level and selling them, and then buying and returning them after falling. So buying is still low, selling is still high, but the operating procedures are reversed.